Wiper blades are a high use item on automobiles and require frequent replacing during the operative life of an automobile primarily due to the aging of the elastomeric material from which the wiper blade is manufactured. Aging of the wiper is a function of the exposure of the wiper blade to the environment and of the external forces exerted on the wiper blade from the mounting arms and the curvature of the windshield glass over which the wiper blade is operated.
To develop improved wiper blades and to enhance their overall performance, it is preferable to replicate the real world utilization of the wiper blades in the laboratory, particularly under lab conditions that can accelerate the aging process. Laboratory testing of wiper blades would require a process and a test fixture by which the wiper blades can be subjected to accelerated tests. Historically, such a process and test fixture has not been developed adequately.
In order to replicate and improve wiper blade performance, the test fixture must be capable of reproducing the permanent set, stress and aging that the wiper blade is subjected to over time. Furthermore, the structural environment in which the wiper blades are to operate can vary significantly from one type or model of vehicle to the other. Accordingly, the test fixture must have sufficient flexibility to vary the parameters under which wiper blades can be operated. For example, the curvature of the windshield glass varies substantially from vehicle to vehicle. The spring force or load vector urging the wiper blade against the surface of the windshield can also be a significant variable. The attack angle, which is the angle at which the wiper blade is disposed against the windshield, is also a variable.
Accordingly, it would be desirable to provide a test fixture that can replicate the real world environment for the testing of wiper blades in a laboratory in which the test fixture will have sufficient flexibility to vary the operative parameters under which the wiper blades can be operable from one vehicle to another and within the same vehicle.